Globally flooding is becoming more and more frequent due to climate change and the increase in development on floodplains. The Associated of British Insurers (ABI) released figures indicating that 486,000 claims for flood and storm damage were received in 2012, resulting in £1.19 billion in insurance payouts, leading the ABI to declare flooding to be the greatest natural threat currently facing the UK.
Flooding is generally unpredictable in that it is often not possible to know in advance exactly when flooding will occur, for how long it will last and what the total volume of floodwater will be. In some circumstances significant volumes of floodwater can accumulate in under a few hours with very little advance warning.
It is desirable to put flood defences in place as soon as possible after the risk of flooding has been identified, since typically early deployment of such defences will reduce or even entirely eliminate the damage caused by flooding.
Prior art flood barriers that are easy to rapidly deploy exist. One example is disclosed in WO 2007/000612 A1, which discloses a flood barrier formed from self-filling units that are interconnected by slide-in keys that are inserted into sockets at the end of the units. The keys incorporate ballast for negative buoyancy and are located between adjacent units in the barrier.
Whilst exhibiting several advantageous features, a disadvantage of this flood barrier is that it is of a fixed height. This means that it is not possible to guarantee that the height of the barrier will be sufficient to hold back an unexpectedly large volume of floodwater.
Another disadvantage of this flood barrier is that the units it is formed from do not make particularly efficient use of the space available during transit or storage.
A further disadvantage of this flood barrier is that it is relatively inflexible with regard to interconnection options between adjacent units forming the barrier. In particular, adjacent units can only be connected to one another in an end-to-end configuration. This means that the depth of this barrier is fixed at the width of a single unit; i.e. the barrier is only a single unit deep. Additionally, one or more curved units are needed if a barrier having a curved profile is required.